1. Field of the Invention
The present invention relates to a multi-stages automatic transmission for a vehicle, and more particularly, to a multi-stages automatic transmission for a vehicle equipped with a gear train embodying 10 forward speeds and 1 reverse speed with gear efficiency 98.6%.
2. Description of Related Art
Recently, the technology development need for performance improvement has emerged similarly in the power train field by requirement of a higher need for fuel efficiency improvements due to strengthening of environmental regulations or rising oil prices.
Appropriate power train technologies corresponding to the need have been provided, including an engine downsizing technology and a multi-staging technology of an automatic transmission. The engine downsizing has merits of reducing weight and improving fuel efficiency, and particularly, the automatic transmission multi-staging has merits of securing drivability and competitiveness of fuel efficiency at the same time through design of an excellent gear ratio in terms of power performance and fuel efficiency by using more shift stages as compared to a 4-speed (or 5-speed), and 1 reverse speed automatic transmission.
An instance of such multi-staging of the automatic transmission, includes an 8 forward speed and 1 reverse speed automatic transmission by combining three planetary gear sets and six friction elements, and 9 forward speed and 1 reverse speed automatic transmission by combining four planetary gear sets, four friction elements and two dog clutches.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.